A variety of different types of power saw are presently available. Chain saws are popular because they are powerful and capable of operating at high speed. Chain saws are, however, hazardous to use and are only suitable for use when cutting materials such as wood.
Banded saws are also popular, however, the conventional band saw is not readily portable and it is difficult to use in confined spaces. Skill saws and jigsaws are also difficult to use in confined spaces and are not capable of forming a long deep cut.
I have found that it is possible to impart orbital and reciprocating movement to a special purpose saw blade in a manner which will permit a high speed cutting action in a saw which is capable of forming a deep kerf which has a substantial length.
I have also found that it is possible to improve the efficiency with which a saw blade removes material from a kerf by forming the blade so that the cutting edges thereof extend obliquely from opposite sides of an apex which is located between the ends of the blade and by forming the saw teeth so that they are angularly inclined in a direction away from the apex on opposite sides of the apex.
I have also found that it is possible to increase the efficiency of operation of a saw by mounting two saw blades in a side-by-side relationship and driving the saw blades in orbital paths which are out of phase with respect to one another.
According to one aspect of the present invention there is provided a saw which comprises an elongated body having a proximal end and a distal end, a cutting edge extending along the first edge of the body, said cutting edge having first and second portions of its length which are angularly inclined with respect to one another from an apex located at the junction of the first and second portions, first saw teeth formed on said first portion of said cutting edge, said first saw teeth being angularly inclined toward said proximal end, second saw teeth formed on said second portion of said cutting edge, said second saw teeth being angularly inclined toward said distal end such that, in use, when the apex of the blade rests in a kerf and the proximal end of the blade is displaced in an orbital path the first and second portions of the cutting edge will be driven in opposite orbital directions in first and second orbital cutting paths to cut and displace material in opposite directions from opposite sides of the apex.
According to a further aspect of the invention there is provided a saw blade support structure and a saw blade each having a proximal end and a distal end, said blade having a pair of cutting edges which are angularly inclined with respect to an apex which is located therebetween, coupling means slideably and pivotally connecting the distal end of the saw blade and the support means in close proximity to the apex of the cutting edge, drive means at the proximal end of the support structure engaging the proximal end of the blade and being operable to drive the proximal end of the blade in an orbital path with respect to the support structure such that the cutting edges of the saw blade are driven in opposite rotational directions in first and second orbital paths to cut and displace material in opposite directions from opposite sides of the apex in use.
According to yet another aspect of the invention there is provided a blade support structure and at least two saw blades each having a proximal end and a distal end, said saw blades each having a cutting edge and being arranged with their cutting edges located in a side-by-side relationship to form a common kerf in use, coupling means slideably and pivotally connecting the saw blades to the support structure intermediate the ends of the saw blade to permit relative movement of the saw blades with respect to the support structure and one another, drive means at the proximal end of the support structure, said drive means engaging the proximal ends of the blades and being operable to drive the proximal ends in orbital paths, the proximal ends of the saw being spaced from one another along the orbital path so as to be out of phase with one another to enhance the efficiency of the cutting action.
According to a still further aspect of the invention there is provided a saw for driving a saw blade to and fro along a cutting path, the saw blade being longitudinally elongated and having first and second cutting edges which are angularly inclined from an apex toward the proximal and distal ends of the blade respectively and pivot means located on the blade in the proximity of the apex, the pivot means having an axis about which the blade may pivot, said saw comprises a saw frame having a proximal end and a distal end, crank means at the proximal end of the frame for mounting the proximal end of the blade on the frame for orbital and reciprocal movement relative to the frame, support means on the frame remote from the crank means for supporting the pivot means of the blade for rotational movement about its axis and for reciprocating movement in the direction of the longitudinal extent of the blade.